Telematics services are services that are provided by a call center to a vehicle and/or to the operator of a vehicle that relate to various needs of the vehicle or the operator. Telematics services commonly include, but are not limited to, the remote monitoring of vehicle maintenance needs, the provision of turn by turn navigation guidance, the coordination of emergency services during vehicle emergencies, the provision of door unlock services when they vehicle's owner is locked out of the vehicle, and the provision of theft tracking services after a vehicle has been stolen, to name just a few.
A telematics service system includes a telematics unit mounted to the vehicle, a call center located remotely from the vehicle, and a communication network that communicatively connects the two. The telematics unit is configured to communicate with both the call center and the vehicle's bus and is therefore capable of communicating various facets of the vehicle's status to the call center.
Historically, the telematics unit has been embedded in the vehicle (i.e., mounted to the vehicle during vehicle assembly) and therefore available to the operator throughout the operator's ownership of the vehicle. With an embedded telematics unit, the operator need only contact the call center and request activation of the embedded telematics unit in order to receive the telematics services.
Because of the popularity of telematics services, aftermarket telematics units are beginning to enter the market place. Such aftermarket telematics units make it possible for drivers of vehicles that lack an embedded telematics unit to, nevertheless, receive some or all of the available telematics services. The aftermarket telematics unit may be mounted to the vehicle and may be wired into to the vehicle's electrical system or battery to draw the power that is needed to operate the aftermarket telematics unit.
In a known example, to receive electrical power from the vehicle, the aftermarket telematics unit includes a constant power line, a switched power line, and a ground line that are configured to be connected to a constant power line, a switched power line, and a ground line, respectively, of the vehicle. When correctly connected to the vehicle, the aftermarket telematics unit is configured to operate in an on-mode when the vehicle is on (e.g., when the vehicle's ignition is turned to either the run or the accessory position), to operate in a standby-mode when the vehicle is off (e.g., when the vehicle's ignition is turned to the off position), and to operate in an off-mode when the vehicle has been turned off for greater than a predetermined length of time, typically five consecutive days. Accordingly, the aftermarket telematics unit typically transitions back and forth between the on-mode and the standby-mode, and will only rarely enter the off-mode. This corresponds with the typical vehicle use case where the vehicle is driven at least once every couple of days and only rarely left off for more than five consecutive days.
When in the on-mode, the aftermarket telematics unit is configured to provide its full range of services to the vehicle and the operator. All of its systems are activated and ready to receive commands/inputs. When in the standby-mode, the majority of the systems of the aftermarket telematics unit are powered down and only a few of the aftermarket telematics unit's systems remain either activated or cycle through alternating periods of sleep and wakefulness. This allows the aftermarket telematics unit to receive communications from the call center even while the vehicle is turned off yet avoids causing excessive battery drain. When in the off-mode, virtually all of the systems of the aftermarket telematics unit are powered down to minimize battery drain. The only function performed by the aftermarket telematics unit while in the off-mode is to monitor the vehicle's switched power line to determine when the vehicle has been turned back on. Once the vehicle is turned back on, the aftermarket telematics unit will transition from the off-mode directly to the on-mode. This is referred to as a “cold start”.
If the three electrical lines of the aftermarket telematics unit are not connected to the correct respective electrical lines of the vehicle, some or all of the proper operating modes might be unavailable.